Since the building space is limited then i suggest an option cvould be to introduce a shopping center of complex.... how this would work is that you would buy the shopping centre for atleast £400,000 and then you can set 3 shops in its options that work like normal shops
Or instead of buying it for a high price you buy at a lower price and have to pay rent for your shops being there:
so buy the shopping mall for 200,000 and then pay 5% of the shops value every month
that means with a furniture shop / DIY shop and Grocery you pay 2 % of those buildings value which would be 18,000
but if you didn't think it was enough to justify it then 25% would be 90,000
This all means that you can get more space for shops and factories since the shopping mall would only be 1 square
What do people think???